Skip to content
Login Register

#infrared

11 public questions tagged with this topic.

Applications of EM Waves in Communication and Medicine

Which type of electromagnetic waves are emitted by hot bodies and molecules?

**Radio waves** effective for long-distance communication because low frequency waves diffract around Earth curvature and reflect from ionosphere, enabling beyond line-of-sight, used in AM (≈10⁶ Hz) ground wave, short wave sky wave. Microwaves used for satellite due to high frequency penetrates ionosphere and directional beam. The document states that infrared waves are produced by hot bodies and molecules, often referred to as heat waves. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Infrared waves, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Applications of EM Waves in Communication and Medicine

View Details
Applications of EM Waves in Communication and Medicine

Which type of electromagnetic waves are produced by the vibration of atoms and molecules?

**Microwaves in ovens** cause water molecules to rotate at 2.45 GHz, friction heats food, penetration depth few cm, efficient heating, also radar uses reflection of microwaves from objects, Doppler shift measures speed, medical diathermy uses microwaves for tissue heating. The document states that infrared waves are produced by the vibration of atoms and molecules. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Infrared waves, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Applications of EM Waves in Communication and Medicine

View Details
Production of EM Waves and Hertz Experiment

Which electromagnetic waves are used in remote switches of household electronic systems?

**Hertz experiment** used induction coil connected to two rods with gap, spark produced oscillating charge, emitted EM wave, received by loop with gap sparking when E induced, measured wavelength by standing wave, demonstrated EM wave properties, validating Maxwell. Infrared waves are widely used in remote switches for devices like TVs and hi-fi systems, as mentioned in the document. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Infrared waves, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Production of EM Waves and Hertz Experiment

View Details
Energy, Intensity and Momentum of EM Waves

What is the approximate wavelength range of infrared waves as per the document?

**Momentum of EM wave** p = U/c, U energy, radiation pressure exerts force F = I A/c, small but measurable, comet tail pushed by sunlight, solar sail concept. For E₀=45 V/m, B₀=1.5×10⁻⁷ T, intensity I =0.5×3×10⁸×8.85×10⁻¹²×45²≈2.69 W/m². The document states that infrared waves range from 1 mm to 700 nm . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 1 mm to 700 nm, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Energy, Intensity and Momentum of EM Waves

View Details
Infrared, Visible Light and Applications

Why are infrared waves used in thermal imaging devices?

**Infrared waves** λ≈700 nm to 1 mm, f≈10¹² to 4×10¹⁴ Hz, produced by hot bodies and molecular vibrations, wavelength range as per document 700 nm-1 mm, used in remote sensing because IR penetrates haze, thermal imaging detects IR emitted by objects, remote controls, effective for sensing temperature. Infrared waves are emitted by objects proportionate to their temperature, allowing thermal imaging devices to detect and map these emissions as temperature variations. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Their temperature relation, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

View Details
Infrared, Visible Light and Applications

Why are infrared waves used in remote switches of household electronic systems?

**Infrared waves** λ≈700 nm to 1 mm, f≈10¹² to 4×10¹⁴ Hz, produced by hot bodies and molecular vibrations, wavelength range as per document 700 nm-1 mm, used in remote sensing because IR penetrates haze, thermal imaging detects IR emitted by objects, remote controls, effective for sensing temperature. The document mentions that infrared waves are emitted by electronic devices like LEDs and are widely used in remote switches due to their ability to transmit signals effectively over short distances. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields They transmit signals effectively, illustrating EM wave transverse

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

View Details
Infrared, Visible Light and Applications

Why are infrared waves often associated with thermal imaging?

**IR effectiveness in remote sensing** because IR scattered less than visible by atmosphere, can detect heat signatures, used in satellite imaging for vegetation, moisture, military night vision, illustrating application based on thermal emission and low scattering. Infrared waves are emitted by objects based on their temperature, and detectors can sense these emissions to map temperature variations, making them ideal for thermal imaging. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Temperature-dependent emission, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

View Details
Ultraviolet, X-rays, Gamma Rays and Their Properties

Why are electromagnetic waves classified into different types in the spectrum?

**Gamma rays** λ10¹⁹ Hz, produced by nuclear transitions and radioactive decay, associated with nuclear processes because nuclear energy levels MeV vs atomic eV, highest photon energy, used in cancer treatment due to high penetration and cell damage, also sterilization, astronomy. Electromagnetic waves are classified based on their frequency (or wavelength), which determines their energy, interaction with matter, and applications. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Their frequency or wavelength, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Ultraviolet, X-rays, Gamma Rays and Their Properties

View Details
Infrared, Visible Light and Applications

Why are infrared waves sometimes referred to as heat waves?

**Infrared waves** λ≈700 nm to 1 mm, f≈10¹² to 4×10¹⁴ Hz, produced by hot bodies and molecular vibrations, wavelength range as per document 700 nm-1 mm, used in remote sensing because IR penetrates haze, thermal imaging detects IR emitted by objects, remote controls, effective for sensing temperature. The document explains that infrared waves are absorbed by water molecules, increasing their thermal motion and thus heating the material. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields They increase thermal motion in materials, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

View Details
Electromagnetic Spectrum - Radio Waves and Microwaves

Why do microwaves heat food more effectively than infrared waves in domestic microwave ovens?

**Hertz experiment** produced radio waves using spark gap LC oscillator, detected with loop antenna, confirming Maxwell's prediction, frequency ≈10⁸ Hz, wavelength ≈3 m, demonstrating EM waves travel at c, transverse, can be reflected, refracted, polarized. Microwaves are tuned to the resonant frequency of water molecules, causing them to oscillate and generate heat via friction, whereas infrared waves primarily heat surfaces through absorption. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Resonance with water molecules, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Electromagnetic Spectrum - Radio Waves and Microwaves

View Details
Infrared, Visible Light and Applications

What is the wavelength range of infrared waves as per the document?

**IR effectiveness in remote sensing** because IR scattered less than visible by atmosphere, can detect heat signatures, used in satellite imaging for vegetation, moisture, military night vision, illustrating application based on thermal emission and low scattering. The document states that infrared waves range from 1 mm to 700 nm . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 1 mm to 700 nm, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

View Details